/*
 * jPOS Project [http://jpos.org]
 * Copyright (C) 2000-2015 Alejandro P. Revilla
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.jpos.iso.channel;

import org.jpos.iso.*;

import java.io.IOException;
import java.net.ServerSocket;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

/**
 * ISOChannel implementation.
 *
 * @author apr@jpos.org
 * @version $Id$
 * @see ISOMsg
 * @see ISOException
 * @see ISOChannel
 */
public class GZIPChannel extends BaseChannel {
	public GZIPChannel() {
		super();
	}

	/**
	 * Construct client ISOChannel
	 *
	 * @param host server TCP Address
	 * @param port server port number
	 * @param p    an ISOPackager
	 * @see ISOPackager
	 */
	public GZIPChannel(String host, int port, ISOPackager p) {
		super(host, port, p);
	}

	/**
	 * Construct server ISOChannel
	 *
	 * @param p an ISOPackager
	 * @throws IOException
	 * @see ISOPackager
	 */
	public GZIPChannel(ISOPackager p) throws IOException {
		super(p);
	}

	/**
	 * constructs a server ISOChannel associated with a Server Socket
	 *
	 * @param p            an ISOPackager
	 * @param serverSocket where to accept a connection
	 * @throws IOException
	 * @see ISOPackager
	 */
	public GZIPChannel(ISOPackager p, ServerSocket serverSocket)
			throws IOException {
		super(p, serverSocket);
	}

	/**
	 * @param len the packed Message len
	 * @throws IOException
	 */
	protected void sendMessageLength(int len) throws IOException {
		serverOut.write(len >> 8);
		serverOut.write(len);
	}

	/**
	 * @return the Message len
	 * @throws IOException, ISOException
	 */
	protected int getMessageLength() throws IOException, ISOException {
		int l = 0;
		byte[] b = new byte[4];
		while (l == 0) {
			serverIn.readFully(b, 0, 2);
			l = ((int) b[0] & 0xFF) << 8 | (int) b[1] & 0xFF;
			if (l == 0) {
				serverOut.write(b);
				serverOut.flush();
			}
		}
		return l;
	}

	protected void sendMessage(byte[] b, int offset, int len)
			throws IOException {
		GZIPOutputStream gzip = new GZIPOutputStream(serverOut);
		gzip.write(b, offset, len);
		gzip.finish();
		gzip.flush();
	}

	protected void getMessage(byte[] b, int offset, int len) throws IOException, ISOException {
		int total = 0;
		GZIPInputStream gzip = new GZIPInputStream(serverIn);
		while (total < len) {
			int nread = gzip.read(b, offset, len - total);
			if (nread == -1) {
				throw new ISOException("End of compressed stream reached before all data was read");
			}
			total += nread;
			offset += nread;
		}
	}
}

